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GET /api/patches/2196513/?format=api
{ "id": 2196513, "url": "http://patchwork.ozlabs.org/api/patches/2196513/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260214131659.31378-4-shentey@gmail.com/", "project": { "id": 14, "url": "http://patchwork.ozlabs.org/api/projects/14/?format=api", "name": "QEMU Development", "link_name": "qemu-devel", "list_id": "qemu-devel.nongnu.org", "list_email": "qemu-devel@nongnu.org", "web_url": "", "scm_url": "", "webscm_url": "", "list_archive_url": "", "list_archive_url_format": "", "commit_url_format": "" }, "msgid": "<20260214131659.31378-4-shentey@gmail.com>", "list_archive_url": null, "date": "2026-02-14T13:16:59", "name": "[3/3] target/i386/emulate/x86_decode: Actually use stream in decode_instruction_stream()", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "618c4fc9a5befdd72b0c76792e2b6d1f676047d5", "submitter": { "id": 83251, "url": "http://patchwork.ozlabs.org/api/people/83251/?format=api", "name": "Bernhard Beschow", "email": "shentey@gmail.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260214131659.31378-4-shentey@gmail.com/mbox/", "series": [ { "id": 492172, "url": "http://patchwork.ozlabs.org/api/series/492172/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=492172", "date": "2026-02-14T13:16:58", "name": "i386 emulate fixes", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/492172/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2196513/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2196513/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>", "X-Original-To": "incoming@patchwork.ozlabs.org", "Delivered-To": "patchwork-incoming@legolas.ozlabs.org", "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256\n header.s=20230601 header.b=Smchuys8;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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helo=mail-wr1-x431.google.com", "X-Spam_score_int": "-20", "X-Spam_score": "-2.1", "X-Spam_bar": "--", "X-Spam_report": "(-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1,\n DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001,\n RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001,\n SPF_PASS=-0.001 autolearn=ham autolearn_force=no", "X-Spam_action": "no action", "X-BeenThere": "qemu-devel@nongnu.org", "X-Mailman-Version": "2.1.29", "Precedence": "list", "List-Id": "qemu development <qemu-devel.nongnu.org>", "List-Unsubscribe": "<https://lists.nongnu.org/mailman/options/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>", "List-Archive": "<https://lists.nongnu.org/archive/html/qemu-devel>", "List-Post": "<mailto:qemu-devel@nongnu.org>", "List-Help": "<mailto:qemu-devel-request@nongnu.org?subject=help>", "List-Subscribe": "<https://lists.nongnu.org/mailman/listinfo/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=subscribe>", "Errors-To": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org", "Sender": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org" }, "content": "Compared to decode_instruction(), decode_instruction_stream() has an additional\nstream parameter which avoids some guest memory accesses during instruction\ndecoding. Both functions defer the actual work to decode_opcode() which would\nset the stream pointer to zero such that decode_instruction_stream() essentially\nbehaved like decode_instruction(). Given that all callers of\ndecode_instruction_stream() properly zero-initialize the decode parameter, the\nmemset() call can be moved into decode_instruction() which is the only other\nuser of decode_opcode(). This preserves the non-zero stream pointer which\navoids extra guest memory accesses.\n\nFixes: 1e25327b244a (\"target/i386/emulate: Allow instruction decoding from stream\")\ncc: qemu-stable\nSigned-off-by: Bernhard Beschow <shentey@gmail.com>\n---\n target/i386/emulate/x86_decode.c | 4 ++--\n 1 file changed, 2 insertions(+), 2 deletions(-)", "diff": "diff --git a/target/i386/emulate/x86_decode.c b/target/i386/emulate/x86_decode.c\nindex 6ad03b71b0..7bbcd2a9a2 100644\n--- a/target/i386/emulate/x86_decode.c\n+++ b/target/i386/emulate/x86_decode.c\n@@ -2088,8 +2088,6 @@ static void decode_opcodes(CPUX86State *env, struct x86_decode *decode)\n \n static uint32_t decode_opcode(CPUX86State *env, struct x86_decode *decode)\n {\n- memset(decode, 0, sizeof(*decode));\n-\n decode_prefix(env, decode);\n set_addressing_size(env, decode);\n set_operand_size(env, decode);\n@@ -2101,6 +2099,8 @@ static uint32_t decode_opcode(CPUX86State *env, struct x86_decode *decode)\n \n uint32_t decode_instruction(CPUX86State *env, struct x86_decode *decode)\n {\n+ memset(decode, 0, sizeof(*decode));\n+\n return decode_opcode(env, decode);\n }\n \n", "prefixes": [ "3/3" ] }